Knitted Fabric for Hook-and-Loop Fastener

ABSTRACT

[Subject] 
     The subject of this invention is to offer an inexpensive tricot stitch, whose adhesive strength with engagement materials increases, whose adhesive strength is the same in case that we adhere engagement materials to it from right side or left side, whose tear strength is very high. 
     [Solution] 
     A knitted fabric for hook-and-loop fastener comprising of tricot stitch for the knitted fabric for hook-and-loop fastener; and the tricot stitch is formed of surface threads, middle threads and backside threads; and each surface threads, middle threads and backside threads has loops at regular intervals, and loops of surface threads are linked to loops of middle threads, and loops of middle threads are linked to loops of backside threads. Furthermore, the piles of surface threads are formed from side to side on the same numbers, and thread direction of a certain loop of surface threads is opposite to thread direction of a corresponding loop of middle threads, and the thread direction of loop of middle threads is opposite to thread direction of a corresponding loop of backside threads.

TECHNICAL FIELD

This invention is related to a knitted fabric for hook-and-loop fastener used as female materials of hook-and-loop fastener.

BACKGROUND OF INVENTION

An adhesive-backed tape has been used for a long time in order to adhere materials easily, for example, fabric and fabric or cloth and cloth. But an adhesive-backed tape has a problem that the adhesion strength will be decline by using many times as a result of adding dust or garbage to the surface of the tape. So, people tend to use a knitted fabric for hook-and-loop fastener instead of an adhesive-backed tape for adhering materials easily.

A tricot stitch is often used as a female material of hook-and-loop fastener for adhering easily. This tricot stitch for hook-and-loop fastener needs durability of many-times attachment and removal, and needs to cut down the manufacturing cost. And it also needs high adhesive strength with engagement materials (e.g. male materials), and needs high durability of the fabric in order not to tear the fabric in case of peeling the engagement materials from the fabric.

Some people have tried to make good knitted fabric for hook-and-loop fastener in relation to these points. For example, JP2005-118360 shows a female material for the purpose of offering fabric for inexpensive and steady hook-and-loop fastener by using polyester fiber.

PRIOR ARTS Patent Publish

-   [Patent publish No. 1] JP2005-118360

DISCLOSURE OF THE INVENTION Problem Invention is to Solve

But a prior female material has a problem that the adhesive strength is different between left and right because piles are lined up at one side of left and right. And it has another problem that the piles of the female materials spend a lot of thread for making larger. It has been impossible to become loops of the female material smaller by applying to prior arts, and impossible to become piles larger in case of the same amount of threads. It needs much cost for becoming them larger because it needs a lot of thread. Furthermore, it has another problem that the strength of the fabric tends to be weak because threads of backside of fabric are only linked to the neighboring threads of middle of fabric and the neighboring threads of surface of fabric.

This invention has been developed in order to solve the above problems. This invention's purpose is to offer an inexpensive fabric for female material of hook-and-loop fastener, which does not occur the differences between left and right related to the adhesive strength, which improves the adhesive strength by using little amount of threads and making large piles, and which improves the fabric tear strength by making loops at backside threads of fabric and linking the loops to the loops of middle threads and surface threads.

Means for Resolving the Problems

In order to solve the problems, the present invention adopts the following means:

A knitted fabric for hook-and-loop fastener comprising of tricot stitch for the knitted fabric for hook-and-loop fastener; and the tricot stitch is formed of surface threads, middle threads and backside threads; and the surface threads form piles that are connected to various engagement materials, and the backside threads form basic fabric by linking to their neighbor threads, and the middle threads link the surface threads with backside threads; and each surface thread, middle thread and backside thread is knitted by repeating desired stitch patterns; and each surface thread, middle thread and backside thread has loops at regular intervals, and loops of surface threads are linked to loops of middle threads, and loops of middle threads are linked to loops of backside threads.

The knitted fabric for hook-and-loop fastener, wherein the piles of surface threads are formed from side to side on desired numbers.

The knitted fabric for hook-and-loop fastener, wherein the piles of surface threads are formed from side to side on the same numbers.

The knitted fabric for hook-and-loop fastener, wherein thread direction of a certain loop of surface threads is opposite to thread direction of a corresponding loop of middle threads, and the thread direction of loop of middle threads is opposite to thread direction of a corresponding loop of backside threads.

The knitted fabric for hook-and-loop fastener, wherein, if we shows stitch patterns of the tricot stitch as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 5-4/9-8/4-5/0-1, stitch pattern of the middle threads is showed refrain of 0-1/1-0/1-0/0-1 and stitch pattern of the backside threads is showed refrain of 4-3/7-7/3-4/0-0; and tear strength of tricot stitch increases as the result that insert portions of backside threads are connected to neighbor threads and loops of backside threads are linked to loops of middle threads.

Effect of the Invention

The tricot stitch of this invention's knitted fabric for hook-and-loop fastener is composed of surface threads and middle threads and backside threads. Some loops are made at each thread at regular intervals. The loops of middle threads are linked to the loops of surface threads, and the loops of middle threads are also linked to the loops of backside threads.

This invention makes the tear strength stronger by linking backside threads to neighboring backside threads and linking the loops of backside threads to the loops of middle threads, because the backside threads do not get loose easily in case that a certain portion will be cut off.

Concerning the knitted fabric for hook-and-loop fastener of this invention, piles of surface threads composed of tricot stitch are made from side to side every same numbers. So, the adhesive strength is the same in case that engagement materials such a male material adhere to the fabric from left side and in case that engagement materials adhere to the fabric from right side. We do not need to consider which directions we should adhere the engagement materials from.

Concerning the knitted fabric for hook-and-loop fastener of this invention, the direction of the threads composed of loops is opposite to between surface threads and middle threads, and between middle threads and backside threads. So, it is possible for us to keep the loops smaller because the looseness of the loops is offset each other. Therefore, we can decrease the amount of threads that are used as loops of surface threads, and we can keep the piles bigger and higher because the amount of threads for piles increases instead of decreasing the amount of surface threads for loops. Concerning the fabric of this invention, the adhesive strength with engagement materials improves by keeping the surface piles bigger and higher.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 A longitudinal view of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 2 An explanatory view about surface threads of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 3 An explanatory view about a stitch pattern among surface threads, middle threads and backside threads of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 4 An explanatory view about surface threads of knitted fabric for hook-and-loop fastener relating to another embodiment

FIG. 5 An explanatory view about backside threads of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 6 A reference view about linking condition among surface threads, middle threads and backside threads of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 7 A reference view that shows knitting condition of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 8 An experimental data that shows tear strength of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 9 An experimental data that shows tear strength of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 10 A edge side macrophotography about piles of knitted fabric for hook-and-loop fastener relating to an embodiment

FIG. 11 A edge side macrophotography about piles of knitted fabric for hook-and-loop fastener relating to an comparative example

DETAILED DESCRIPTION OF THE INVENTION

The female materials for hook-and-loop fastener are mainly composed of base tapes, cohesive layers and tricot stitches. The tricot stitches are adhered to the base tapes by the cohesive layers. The surface threads, the middle threads and the backside threads independently have a certain stitch pattern, and the tricot stitches are composed of the combination of the surface threads, middle threads and backside threads.

For example, nylon fiber or polyester are used for threads of this invention, but the threads are not limited to these fiber.

Tricot stitches of this invention have mainly below features.

The threads of the backside have insert portions which link to the neighbor threads of middle and surface for making basic fabric, and also have some loops at regular intervals. The loops are linked to the above loops formed by the middle threads, and adhesive strength of the fabric improves.

The threads of the surface have loops at the center of the line, and have piles at both sides of the line alternately. That is to say, a certain loop is formed at center of thread, and a certain pile is formed at left side, and a certain loop is formed at next center of thread, and a certain loop is formed at right side. Loops and piles are formed from side to side.

By making piles from side to side for adhering engagement materials such as male materials, the fabric has the same adhesive strength in case of adhering engagement materials from upper right or from upper left.

The numbers of piles that are formed at one side is optional or free. For example, it is possible to make piles one by one from side to side, it is also possible to make two piles at left side and two piles at right side.

Concerning the tricot stitch of this invention, loops of surface threads, loops of middle threads and loops of backside threads are linked to each other at regular intervals. The direction of the surface threads for the loops is opposite to the direction of the middle ones, and the direction of the middle ones is opposite to the direction of the backside ones.

That is to say, in case that the loops of the surface threads are made by anti-clockwise rotation, the loops of the middle threads linked to their surface loops are made by clockwise rotation, and the loops of the backside threads linked to their middle loops are made by anti-clockwise rotation.

The loops of surface threads, middle threads and backside threads get loose and become bigger because the loosen force opposite to direction of the threads is generated. The piles of surface threads become relatively smaller as the result that the loops of surface threads become bigger.

Concerning this invention, the direction between surface threads and middle threads, and the direction between middle threads and backside threads are respectively opposite way. So, the loosen force is offset each other because their loops gain opposite loosen force, when each loop gains the loosen force.

That is to say, in case that the backside thread loops gain the loosen force at clockwise rotation, the middle thread loops gain the loosen force at anti-clockwise rotation. So, the loosen force of such loops is offset. In case that the middle thread loops gain the loosen force at anti-clockwise rotation, the surface thread loops gain the loosen force at clockwise rotation. So, the loosen force of such loops is offset. By this invention, we can keep the loops small when the loops gain the loosen force, because the each loosen force is offset.

We can keep each loops small, and also keep surface loops small, therefore, we can keep piles of surface high and big, because we can spend more amount of threads as surface piles as the result of keeping surface loops smaller.

The female materials for knitted fabric for hook-and-loop fastener that this invention's tricot stitch is applied to are mainly used as a disposable hook-and-loop fastener or a simple adhesive hook-and-loop fastener, especially used as a disposable diaper (nappy) favorably. But used objects are not limited to these things.

The thread's size used for tricot stitch of this invention is free, and we can decide in relation to the purpose of the hook-and-loop fastener. For example, if the fabric of this invention is used for a disposable diaper (nappy), the surface threads should be thick (or medium size), the middle threads should be thin and the backside threads should be medium size. And for example, if the fabric of this invention is used for other purposes, the surface threads should be thick (or medium size), the middle threads should be medium size (or thin) and the backside threads should be thick. These sizes are favorable, but sizes are not limited to these examples.

Embodiment 1

We will explain a desirable embodiment about this invention's fabric, referring to FIGS. 1-3 and 5-11. By the way, concerning FIGS. 6 and 7, wavy lines mean surface threads (F), and solid lines mean middle threads (M), and dotted lines mean backside threads (B).

As FIG. 1 shows, this invention's female materials of fabric for hook-and-loop fastener (1) are mainly composed of tricot stitch (2), cohesive layer (3) and base tape (4). The tricot stitch is composed of surface threads (F), middle threads (M) and backside threads (B).

The backside threads (B) form backing fabric by linking to neighbor threads. And the backside threads are adhered to the base tape (4) through the cohesive layer (3).

As FIG. 3 shows, if we shows stitch patterns of this embodiment's tricot stitch as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 5-4/9-8/4-5/0-1, stitch pattern of the middle threads is showed as refrain of 0-1/1-0/1-0/0-1 and stitch pattern of the backside threads is showed as refrain of 4-3/7-7/3-4/0-0.

FIG. 6 shows a combination of a certain line of tricot stitch that is composed of each pattern of surface threads, middle threads and backside threads. Furthermore, the tricot stitch is composed of several lines, and FIG. 7 shows it.

In FIG. 7, each surface thread is linked to each middle thread at positions of mark “cross (x)”, and the surface threads stand up and form piles at midpoints between “cross (x)” and “cross (x)”.

The tricot stitch composed of the above stitch pattern shows below effective features in comparison with prior arts.

As FIG. 5 shows, backside threads (B) are composed of insert portions (10) that meander from side to side and loops (8) that are formed continuously at midpoint between them. Backside threads of prior arts had only insert portions, but backside threads of this invention have loops in addition to insert portions.

As FIG. 7 shows, insert portions link to the neighbor loops of middle threads (M) or surface threads (F), and backside threads form basic fabric. But if the backside threads have only insert portions, they get loose easily in case that one portion of them is cut off. Therefore, a prior fabric had the problem that the tear strength became very weak.

The tricot stitch of this embodiment has loops (8) in addition to insert portions (10), and the loops of backside threads are linked to the loops (7) of middle threads. If a certain portion of backside threads is cut off, it is possible to keep the connection between loops of backside threads and loops of the above middle threads, because loops of backside threads linked to loops of middle threads are left at fore-and-aft of the cut-off point. Therefore, the tear strength of this invention's fabric has improved because backside threads do not get loose easily.

We will testify that the tear strength of this invention's fabric has improved by making loops (8) at backside threads (M) as following:

We prepared two kinds of five pieces about fabric, one is the fabric that is knitted in 20-course and have both loops and insert portions at backside threads, the other is the fabric that is knitted in 20-course and have only insert portions at backside threads. And we calculated their tear strength by criteria of JIS L 1018 A (Pendulum method). In this experiment, firstly, we cut off the fabric by 2 cm, secondly, we exert a force on the fabric from center to both side, and thirdly, we measure at what force the fabric tears.

The FIG. 8 shows the result of the experiment.

At the table of FIG. 8, numbers in parentheses at sample lines means sample numbers used for this experiment. To be concrete, the number means as following:

A sample (1): a fabric that is knitted in 20-course and have loops in backside threads A sample (2): a fabric that is knitted in 20-course and does not have loops in backside threads

An above “Wales * 1” line in “tear strength” line means tear strength figures of upper side of fabric, namely, tear strength figures we cut off the start point of knitting. A below “Wales * 2” line in “tear strength” line means tear strength figures of lower side of fabric, namely, tear strength figures we cut off the end point of knitting. A unit of the figures is “N (Newton)”, and the higher the figures are, the higher the tear strength is (i.e. the stronger the fabric is).

And “N=” means the number of times we measured. For example, “N=1” means first measurement, and “N=2” means second measurement. The course number means stitch numbers in 1-inch fabric. The higher the course number is, the denser the fabric density is.

As table of FIG. 8 shows, we succeeded in demonstrating that the tear strength of sample (1) that has loops in backside threads became higher than the one of sample (2), even if we cut off the fabric by 2 cm from upper side or we cut off it by 2 cm from lower side. For example, in case that we cut off the fabric by 2 cm from upper side, an average of sample (1) was 6.2N and an average of sample (2) was 2.7N. On the other hand, in case that we cut off the fabric by 2 cm from lower side, an average of sample (1) was 6.0N and an average of sample (2) was 3.2N. Thus we succeeded in demonstrating that the tear strength of this embodiment's fabric that has loops in backside threads doubled in comparison with the fabric that does not have loops in backside threads, in case of fabric knitted in 20 course.

As next experiment, we prepared two kinds of fabrics from 20 course knitting to 40 course knitting at 5 course intervals, one is the fabric that have loops in backside threads, the other is the fabric that does not have loops in backside threads. And we measured their tear strength by criteria of JIS L 1018 A (Pendulum method).

The FIG. 9 shows the result of the experiment.

At the table of FIG. 9, numbers in parentheses at sample lines means sample numbers used for this experiment. To be concrete, the number means as following:

A sample (1): a fabric that is knitted in 20-course and have loops in backside threads A sample (2): a fabric that is knitted in 25-course and have loops in backside threads A sample (3): a fabric that is knitted in 30-course and have loops in backside threads A sample (4): a fabric that is knitted in 35-course and have loops in backside threads A sample (5): a fabric that is knitted in 40-course and have loops in backside threads A sample (6): a fabric that is knitted in 20-course and does not have loops in backside threads A sample (7): a fabric that is knitted in 25-course and does not have loops in backside threads A sample (8): a fabric that is knitted in 30-course and does not have loops in backside threads A sample (9): a fabric that is knitted in 35-course and does not have loops in backside threads A sample (10): a fabric that is knitted in 40-course and does not have loops in backside threads

As table of FIG. 9 shows, in case that we cut off the fabric by 2 cm from upper side, sample (1) was 6.2N, sample (2) was 7.1N, sample (3) was 8.7N, sample (4) was 8.9N, sample (5) was 9.1N, sample (6) was 2.8N, sample (7) was 5.9N, sample (8) was 6.9N, sample (9) was 6.9N, sample (10) was 10.3N.

On the other hand, in case that we cut off the fabric by 2 cm from upper side, sample (1) was 6.0N, sample (2) was 6.5N, sample (3) was 7.8N, sample (4) was 9.3N, sample (5) was 9.4N, sample (6) was 2.6N, sample (7) was 4.5N, sample (8) was 5.5N, sample (9) was 6.6N, sample (10) was 10.7N.

Thus, we succeeded in demonstrating that the tear strength of sample (1)-(4) that has loops in backside threads became higher than the one of sample (6)-(9) that does not have loops in backside threads.

We succeeded in demonstrating that the tear strength of the fabric that has loops in backside threads increases about 1.2-2.3 times in comparison with the fabric that does not have loops in backside threads, in case of fabric knitted in 20-35 course (i.e. sample (1)-(4) and (6)-(9)), though we cannot find clear differences about the fabric knitted in 40 course (i.e. sample (5) and (10)).

Therefore, using this embodiment's fabric that has loops in backside threads, we can attach or remove this tricot stitch with engagement materials such as male materials more times, because the fabric does not tear easily.

As FIG. 2 shows, surface threads (F) of this embodiment are composed of piles (5) that meander from side to side and loops (6) that are formed continuously at midpoint between them. The piles do not twine into neighbor threads and stand up like gabled arch. They form the portions that adhere to engagement materials such as male materials.

Piles (21) are evenly arranged from side to side at the center of loops in regard to the surface threads of this embodiment. That is because the fabric has the same adhesive strength in case that the engagement materials adhere to it from right or left. It is ideal to keep the piles in a vertical position. But, in fact, piles at right side stand up with a right inclination, and piles at left side stand up with a left inclination. So, if the piles are formed at only one side of right or left, all piles stand up with the same side inclination. As the result, the adhesive strength is different in case of adhering engagement materials from right angle and adhering engagement materials from left angle.

This invention's female materials (1) of knitted fabric for hook-and loop fastener are favorably used for a disposable paper diaper (nappy) etc. Using them for a disposable paper diaper, engagement materials are generally adhered to female materials from right side and left side. If the adhesive strength is different in case of adhering engagement materials from right angle and adhering engagement materials from left angle, there are problems in such fabric because it is easy to remove engagement materials at one side, and it is difficult to remove them at the other side. If piles of fabric are formed at only one way of right or left, it will be possible to divide the fabric into two pieces at the center line, and combine the two pieces after inverting one piece. Thought it can be possible to solve the above problem by using this way, the way gives us a lot of time and trouble.

This invention's knitted fabric for hook-and-loop fastener does not arise differences of adhesive strength even if we adhere engagement materials to it from both sides. So the above problem is solved because we need not to consider the direction to fix the fabric.

Piles stand up at both side of right and left alternately, and engagement materials easily adhere to female materials in case to adhering the engagement materials from right side and left side.

Concerning the tricot stitch (2) of this embodiment, loops of surface threads (F) are linked to loops of middle threads (M), and loops of middle threads (M) linked to loops of backside threads (B). As FIG. 3 shows, the direction of threads of surface loops is opposite to the direction of threads of middle loops, and the direction of threads of middle threads is opposite to the direction of threads of backside threads.

As a certain loop of FIG. 3 shows, in case that the thread direction of surface loop is at anti-clockwise rotation, the corresponding thread direction of middle loop is at clockwise rotation. And in case that the thread direction of middle loop is at clockwise rotation, the corresponding thread direction of backside loop is at anti-clockwise rotation.

By this idea, it is possible to keep piles higher and bigger at little amount of threads about tricot stitch (2) of this embodiment. The each surface thread makes piles and loops. So, when we spend a large amount of threads into loops, that is to say, we make loops bigger, we relatively spend a small amount of threads into piles, that is to say, we can not make piles bigger.

Generally speaking, it is to be desirable that we make piles higher and bigger because the adhesive strength of fabric improves. It is very important for us to increase an amount of threads for piles as the result of decreasing an amount of threads for loops.

We succeeded in keeping the amount of threads for loops less as the result that the each directions of loops threads were opposite way among surface threads, middle threads and backside threads.

If we made each loop small, the loops have gotten loose because the loops have gained opposite force to direction of threads, as time passed. Concerning the loops of surface threads, middle threads and backside threads of this embodiment, the opposite force to direction of threads is offset, the invention result in restraining the looseness of the loops. Therefore, we can keep the piles of surface threads higher and bigger, because we can keep the loops of surface threads smaller after making the loops small.

The FIG. 10 shows an enlargement of a certain side of this invention's fabric, which the direction of loops threads is opposite to between surface loops and middle loops, and between middle loops and backside loops.

The FIG. 11 shows an enlargement of a certain side of comparative example's fabric, which the direction of loops threads is same as between surface loops and middle loops, and between middle loops and backside loops.

Each Figure is graduated in 0.5 mm.

Each Figure shows a circle from middle part to upper part, and the circles mean piles that are formed by surface threads. The piles are formed between α (alpha) range in FIG. 10, and the piles are formed between β (beta) range in FIG. 11.

The length of threads of fabric in FIG. 10 is the same as it of the comparative example in FIG. 11, and both of them are knitted in 20-course.

In case that the direction of loops threads between surface and middle, and between middle and backside was opposite to each other (i.e. this embodiment), the height showed about 3.0 mm (about 6 scales), as FIG. 10 shows.

On the other hand, in case that the direction of loops threads between surface and middle, and between middle and backside was same as each other (i.e. comparative example), the height showed about 1.0 mm (about 2 scales), as FIG. 11 shows.

In the case that fabrics are made as the same length, it demonstrated that we could keep piles by forming opposite loops direction among surface, middle and backside three times as high as piles by forming same loops direction among surface, middle and backside.

The piles easily hook on engagement materials and the adhesive strength increases as the result that we keep piles that adhere to engagement materials higher and bigger. Because we can form higher piles without using longer threads, we can cut down on expenses for threads in order to make higher piles.

Embodiment 2

We will explain another embodiment about knitted fabric for hook-and-loop fastener of this invention, referring to the FIG. 4. Tricot stitch of this embodiment is different from it of embodiment 1. Other compositions of this embodiment without tricot stitch are the same as them of embodiment 1.

As FIG. 4 shows, if we shows stitch patterns of this embodiment's tricot stitch as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 4-5/0-1/4-5/0-1/5-4/9-8/5-4/9-8.

That is to say, each two piles (5) is formed from side to side at the center of loops (6). Two piles are formed at right, and two piles are formed at left, and two piles are formed at right, and two piles are formed at left, and this pattern is repeated.

We can make piles that are inclined from side to side by using the above knitting. So, the fabric by this knitting gains the same adhesive strength in case that engagement materials such as male materials adhere to it from upper right or upper left, and we need not to pay attention to directions of adhering.

The tricot stitches of the above embodiments are knitted by knitting machine, raschel knitting machine and so on. Knitting gauges are preferably 7-18 gauges. Knitting courses are preferably 15-50 courses per inch. But knitting conditions are not limited to these examples, and it is possible to knit other conditions in consideration of desired adhesive strength or fabric strength.

We explain the composition of tricot stitch by using stitch patterns in the above embodiments. But their stitch patterns are not limited to the above examples, because desired stitch patterns may change when knitting gauges or knitting arrangements change.

This invention is not limited to the above descriptions, and it is possible to arrange this invention as long as we do not deviate from this invention's gist.

ABOUT MARKS

-   1. Female materials for hook-and-loop fastener -   2. Tricot stitch -   3. Cohesive layer -   4. Base tape -   5. Piles -   6. Loops of surface threads -   7. Loops of middle threads -   8. Loops of backside threads -   10. Insert portions of backside threads -   21 Portion of piles -   22. Portion that loops are linked -   F. Surface threads -   M. Middle threads -   B. Backside threads -   X. Direction of surface threads -   Y. Direction of middle threads -   Z. Direction of backside threads -   α. (Alpha) Pile's height of this embodiment -   β. (Beta) Pile's height of comparative example 

1: A knitted fabric for hook-and-loop fastener comprising: tricot stitch for the knitted fabric for hook-and-loop fastener; and the tricot stitch is formed of surface threads, middle threads and backside threads; and the surface threads form piles that are connected to various engagement materials, and the backside threads form basic fabric by linking to their neighbor threads, and the middle threads link the surface threads with backside threads; and each surface thread, middle thread and backside thread is knitted by repeating desired stitch patterns; and each surface thread, middle thread and backside thread has loops at regular intervals, and loops of surface threads are linked to loops of middle threads, and loops of middle threads are linked to loops of backside threads. 2: The knitted fabric for hook-and-loop fastener according to claim 1, wherein the piles of surface threads are formed from side to side on desired numbers. 3: The knitted fabric for hook-and-loop fastener according to claim 1, wherein the piles of surface threads are formed from side to side on the same numbers. 4: The knitted fabric for hook-and-loop fastener according to claim 1, wherein thread direction of a certain loop of surface threads is opposite to thread direction of a corresponding loop of middle threads, and the thread direction of loop of middle threads is opposite to thread direction of a corresponding loop of backside threads. 5: The knitted fabric for hook-and-loop fastener according to claim 1, wherein, if stitch patterns of the tricot stitch are shown as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 5-4/9-8/4-5/0-1, stitch pattern of the middle threads is showed refrain of 0-1/1-0/1-0/0-1 and stitch pattern of the backside threads is showed refrain of 4-3/7-7/3-4/0-0; and tear strength of tricot stitch increases as the result that insert portions of backside threads are connected to neighbor threads and loops of backside threads are linked to loops of middle threads. 6: A knitted fabric for hook-and-loop fastener comprising: tricot stitch for the knitted fabric for hook-and-loop fastener; and the tricot stitch is formed of surface threads, middle threads and backside threads; and the surface threads form piles that are connected to various engagement materials, and the backside threads form basic fabric by linking to their neighbor threads, and the middle threads link the surface threads with backside threads; and each surface thread, middle thread and backside thread is knitted by repeating desired stitch patterns; and each surface thread, middle thread and backside thread has loops at regular intervals, and loops of surface threads are linked to loops of middle threads, and loops of middle threads are linked to loops of backside threads; and the piles of surface threads are formed from side to side on desired numbers; and thread direction of a certain loop of surface threads is opposite to thread direction of a corresponding loop of middle threads, and the thread direction of loop of middle threads is opposite to thread direction of a corresponding loop of backside threads. 7: The knitted fabric for hook-and-loop fastener according to claim 6, wherein, if stitch patterns of the tricot stitch are shown as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 5-4/9-8/4-5/0-1, stitch pattern of the middle threads is showed refrain of 0-1/1-0/1-0/0-1 and stitch pattern of the backside threads is showed refrain of 4-3/7-7/3-4/0-0; and tear strength of tricot stitch increases as the result that insert portions of backside threads are connected to neighbor threads and loops of backside threads are linked to loops of middle threads. 8: A knitted fabric for hook-and-loop fastener comprising: tricot stitch for the knitted fabric for hook-and-loop fastener; and the tricot stitch is formed of surface threads, middle threads and backside threads; and the surface threads form piles that are connected to various engagement materials, and the backside threads form basic fabric by linking to their neighbor threads, and the middle threads link the surface threads with backside threads; and each surface thread, middle thread and backside thread is knitted by repeating desired stitch patterns; and each surface thread, middle thread and backside thread has loops at regular intervals, and loops of surface threads are linked to loops of middle threads, and loops of middle threads are linked to loops of backside threads; and the piles of surface threads are formed from side to side on the same numbers; and thread direction of a certain loop of surface threads is opposite to thread direction of a corresponding loop of middle threads, and the thread direction of loop of middle threads is opposite to thread direction of a corresponding loop of backside threads. 9: The knitted fabric for hook-and-loop fastener according to claim 8, wherein, if stitch patterns of the tricot stitch are shown as refrain of stitch position from 1 to 9, the stitch pattern of the surface threads is showed as refrain of 5-4/9-8/4-5/0-1, stitch pattern of the middle threads is showed refrain of 0-1/1-0/1-0/0-1 and stitch pattern of the backside threads is showed refrain of 4-3/7-7/3-4/0-0; and tear strength of tricot stitch increases as the result that insert portions of backside threads are connected to neighbor threads and loops of backside threads are linked to loops of middle threads. 